Elop, a Canadian national, joined Nokia from a senior executive position at Microsoft last year. The first non-Finn to lead Nokia, he is under intense pressure to reverse the company’s market share losses to North American and Asian competitors.

“Nokia is at a critical juncture, where significant change is necessary and inevitable in our journey forward,” Elop said. He added the company was aiming at “regaining our smart phone leadership, reinforcing our mobile device platform and realizing our investments in the future.”

Speaking later to analysts in London, he declined to say when Nokia would introduce a new device running on Windows Phone. But he said Nokia won’t bury its own Symbian operating system or the new Meego platform that it is currently developing.

“We need to, and we will, collaborate closely on development … so we can really align and drive the future revolution of the mobile phone,” he said.

Of course, Nokia isn’t the top dog it used to be. But despite a weak presence in the United States, declining market share worldwide and a lack of hit products, the company still sold more phones than any other manufacturer in 2010. Last year, Nokia shipped about 100 million handsets (more than twice as many as Apple sold), according to market research firm IDC. No other partner could give Microsoft that same kind of global reach and scale.

In a way, with Google, it would’ve been just another Android handset maker. The details of its deal with Microsoft likely mean it will be first among equals, a premier partner in the Redmond company’s mobile business. It will also likely benefit, according to some reports, from many millions of dollars in development support from Microsoft, as it makes the transition to their OS. So will Windows Phone get the job done? Not unless Nokia shows some real — and real fast — innovation on the hardware side as well.

INQ Chief Executive Frank Meehan told me today that the Nokia-Microsoft strategic partnership, in which Windows Phone 7 will be the primary operating system for Nokia was “good for both parties.”

Microsoft’s mobile operating system is well-regarded, but it has just 8.5% market share in the U.S., so piggybacking onto Nokia’s huge distribution channels and the billion or so people who use its phones today could provide a new advantage against Google Android and Apple’s iPhone. Working together on a Windows Phone 7 ecosystem would also keep both parties incentivized to make the software a success.

Where two established giants of very different corporate culture, structure and nationality come together to try and play catch up in a business characterised by a new generation of faster moving reptiles, the result is highly unlikely to be productive. I’m willing to bet big money that the partnership will not last more than five years and will fail to produce the cutting edge technology aspired to.

“There is intense heat coming from our competitors, more rapidly than we ever expected. While competitors poured flames on our market share, what happened at Nokia? We fell behind, we missed big trends, and we lost time.”

A dime to a dozen, he’ll lose even more attempting to make his joint venture with Microsoft work.